Flexible lithium ion batteries (LIBs) have recently attracted increasing attention as they show unique promising advantages, such as flexibility, shape diversity, and light weight. Similar to conventional LIBs, flexible LIBs with long cycle life and high-rate performance are very important for applications of high performance flexible electronics. Herein, we report a three-dimensional (3D) web-like binderfree Li4Ti5O12 (LTO) anode assembled from numerous 1D nanowires exhibiting excellent cycling performance with high capacities of 153 and 115 mA·h·g^-1 after 5,000 cycles at 2 C and 20 C, respectively, and excellent rate property with a capacity of 103 mA·h·g^-1 even at a very high current rate of 80 C. Surprisingly, a flexible full battery assembled from the web-like LTO nanostructure and LiMn2O4 (LMO) nanorods exhibited a high capacity of 125 mA·h·g^-1 at high current rate of 20 C, and showed excellent flexibility with little performance degradation even in seriously bent states. 相似文献
Nanocrystalline Li4Ti5O12/Li3SbO4/C composite-prepared by mechanical ball-milling of Li4Ti5O12 (synthesized by aqueous combustion), Li3SbO4 (synthesized by solid state method) and activated carbon, has been investigated as anode in lithium-ion coin cells and compared to pristine Li4Ti5O12. Galvanostatic charge–discharge measurements in the potential window of 0.05–2.0 V show three plateau regions corresponding to Li insertion/extraction in the composite: a large flat plateau at ~ 1.52/1.59 V, followed by a second plateau at ~ 0.75/1.1 V and a sloppy tail at ~ 0.4/0.6 V. While the plateaus at ~ 0.4/0.6 V and ~ 1.52/1.59 V correspond to Li4Ti5O12, the other one at ~ 0.75/1.1 V corresponds to Li3SbO4. At a high rate of ~ 15 C, the capacity for Li4Ti5O12/Li3SbO4/C composite is found to be 105 mAhg?1 retaining ~ 78% of its initial capacity compared to only 58 mAhg?1 (~ 27% of the initial capacity) at 14 C for pristine Li4Ti5O12 up to 100 cycles. Thus, such composite material might find application in lithium-ion batteries requiring high rate of charge and discharge. 相似文献
Li4Ti5O12 (LTO) has attracted considerable attention in lithium-ion battery (LIB) applications because of its favorable characteristics as an anode material. Despite its promise, the widespread use of LTO is still limited primarily due to its intrinsically poor electric and ionic conductivities and high surface reactivity. To address these issues, we designed polygonal nanoarchitectures composed of various Li–Ti oxide crystal polymorphs by a facile synthesis route. Depending on the pH condition, this synthesis approach yields multi-polymorphed Li–Ti oxides where the interior is dominantly composed of a Li-rich phase and the exterior is a Li-deficient (or Li-free) phase. As one of these variations, a polygonal LTO-rutile TiO2 structure is formed. The rutile TiO2 on the surface of this LTO composite significantly improves the kinetics of Li+ insertion/extraction because the channel along the c-axis in TiO2 provides a Li+ highway due to the significantly low energy barrier for Li+ diffusion. Moreover, the presence of rutile TiO2, which is less reactive with a carbonate-based electrolyte, ensures long-term stability by suppressing the undesirable interfacial reaction on LTO.
Li4Ti5O12 (LTO) nanoparticles were successfully synthesized by solvothermal technique using cost-effective precursors in polyol medium and post-annealed at temperatures of 400, 500, and 600 degrees C. The XRD patterns of the samples were clearly indexed to the spinel shaped Li4Ti5O12 (space group, Fd-3 m). The particle size and morphology of samples were identified using field-emission SEM. The electrochemical performance of solvothermal samples revealed fairly high initial discharge/charge specific capacities in the range 230-235 and 170-190 mAh/g, at 1 C-rate, while that registered for the solid-state sample has been 160 and 150 mAh/g, respectively. Furthermore, among these samples, LTO annealed at 500 degrees C exhibited highly improved rate performances at C-rates as high as 30 and 60 C. This was attributed to the achievement of small particle sizes with high crystallinity in nano-scale dimensions and hence shorter diffusion paths combined with larger contact area at the electrode/electrolyte interface. 相似文献
The morphology and electronic structure of a Li4Ti5O12 anode are known to determine its electrical and electrochemical properties in lithium rechargeable batteries. Ag-Li4Ti5O12 nanofibers have been rationally designed and synthesized by an electrospinning technique to meet the requirements of one-dimensional (1D) morphology and superior electrical conductivity. Herein, we have found that the 1D Ag-Li4Ti5O12 nanofibers show enhanced specific capacity, rate capability, and cycling stability compared to bare Li4Ti5O12 nanofibers, due to the Ag nanoparticles (<5 nm), which are mainly distributed at interfaces between Li4Ti5O12 primary particles. This structural morphology gives rise to 20% higher rate capability than bare Li4Ti5O12 nanofibers by facilitating the charge transfer kinetics. Our findings provide an effective way to improve the electrochemical performance of Li4Ti5O12 anodes for lithium rechargeable batteries. 相似文献
Nanocrystalline spinel NiFe2O4 was synthesized by a novel low temperature route. The crystal structure, composition and morphology of the as-prepared powder were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The average diameter of the particles prepared at 700 °C is about 30 nm. The electrochemical reaction mechanism and charge–discharge mechanism of the nanocrystalline NiFe2O4 were proposed based on thermogravimetric analysis (TGA) and cyclic voltammogram study. The charge–discharge tests indicated that the sample calcined at 700 °C shows the highest initial discharge capacity (1400 mAh g−1) attributed to the nanometer size and the better crystallinity of the powder. A discharge capacity stabilizes at about 600 mAh g−1 after 10 cycles. The columbic efficiency is improved. The synthesis method is relatively low cost and convenient for large-scale production. 相似文献
Journal of Materials Science - Porous silicon (PSi) has become one of the current hotspots in lithium-ion anode materials research. However, due to their large volume change in the charge and... 相似文献